Raikkonen has impressed Lotus since joining the team for his Formula 1 comeback after two years in rallying, and was quickest on the first day of winter testing at Jerez last week.

Lopez said Lotus had found Raikkonen to be a totally different character to how he was presented during his last F1 stint.

"For most people it's probably one of the big mysteries, because you hear the hearsay and so forth, but we feel very good with him and he clearly feels at home," Lopez told AUTOSPORT.

"He smiles a lot when he's with us! But most importantly that says he feels more like part of the family."

Lopez added: "I think Kimi has a public image that honestly from what we've seen does not translate into how he really is. He's a very hard worker, very good at providing feedback, and has a good team spirit.

"Once we talked to him, once we understood why he was coming back, we really felt comfortable. If you look at what happened [at the test], nobody can say that he's not on the pace."

Boullier reckons the way Lotus works is proving ideal for Raikkonen.

"We tried to handle his personality and make sure that we don't bother him too much with too many intrusions, and he's a real racer," said Boullier.

"This team is full of proper racing people and he has fitted very well because we speak the same language.

"We are flexible, but our system is very racing-orientated, and that suits him very well."

Autosport.com